How does quantum tunneling help explain alpha decay?

In quantum mechanics, alpha decay occurs when an alpha particle escapes an atomic nucleus despite lacking the energy to overcome the surrounding potential barrier.12

In classical physics, a particle trapped by a potential barrier higher than its own energy would remain confined indefinitely. However, quantum mechanics describes particles as waves that can penetrate these "impassable" barriers. Because the alpha particle has a non-zero probability of existing within the forbidden region of the barrier, it can "tunnel" through it and emerge on the other side.123

This process explains why alpha decay is possible even when the energy of the emitted particle is significantly lower than the height of the nuclear potential barrier. The probability of this tunneling is extremely sensitive to the particle's energy, which accounts for the vast range of observed half-lives among different radioactive isotopes. This same principle of tunneling is utilized in the scanning tunneling microscope to image atomic structures.312